It is a basic mechanical invention that should be quite feasible with existing technology. I know what I want it to do, but I am not sure exactly how it works or what the best design/components could/should be. Therefore, I am looking for the LEAST EXPENSIVE way to get reasonable quality professional assistance with my preliminary design/components/functions, a provisional patent application and a 3-d computerized prototype for presentations to manufacturers.
My main question is if I should go to an engineer and nail down my preliminary design before going to a licensed patent agent/attorney or 3d modeler, or go directly to a patent professional or 3d modeler that is a degreed mechanical engineering for example. I am assuming an engineer might be less expensive for design assistance than an engineer who is also a patent agent/attorney or 3d modeler.